ATP7B and Wilson disease: Besides different ATP7B mutations [8], other genetic variations may influence the variability in WD manifestation, such as apolipoprotein E (APOE), human prion protein (PRNP), 5,10-methylenetetrahydrofolate reductase (MTHFR), the interleukin-1 receptor antagonist (IL1RN), peroxisomal catalase, and other genes [7,9].